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Topic:Disease Etiology
Disease etiology in horses refers to the study of the causes and development of diseases within equine populations. It encompasses various factors, including genetic predisposition, environmental influences, infectious agents, and nutritional imbalances, that contribute to the onset and progression of diseases in horses. Understanding disease etiology is essential for identifying risk factors and implementing preventative measures in equine health management. This topic includes research on pathogen-host interactions, the impact of management practices on disease incidence, and the role of genetic and environmental factors in disease susceptibility. This page compiles peer-reviewed research studies and scholarly articles that explore the mechanisms, contributing factors, and implications of disease etiology in horses.
Fumonisin B1 levels associated with an epizootic of equine leukoencephalomalacia. During the fall of 1989, an episode of equine leukoencephalomalacia involved 18 of 66 purebred Arabian horses at a breeding/training stable in Arizona. Of the 18 horses affected, the condition was fatal in 14. These horses, as well as 48 unaffected horses, had been fed a diet containing a substantial amount of white corn screenings. Gross pathologic findings included liquefactive necrosis in parts of the cerebral white matter and hemorrhagic foci of various sizes in the brain stem. Histopathologic findings included rarefied white matter with pyknotic nuclei and eosinophilic cytoplasm. Thin-lay...
EGF receptor-binding activity in the urine of normal horses and horses affected by chronic laminitis. A heterologous radioreceptor binding assay (RRA) has been developed capable of detecting nanogram amounts of epidermal growth factor (EGF) receptor-binding activity in equine urine. The binding parameters of [125I]mEGF (murine EGF) to EGF receptors on equine plasma membranes are in good agreement with values from other EGF-RRA systems. The dissociation constant estimated from equilibrium methods (KD = 4 X 10(-10) M) is in reasonable agreement with that determined from the rate constants (KD = 6 X 10(-10) M) and is in good agreement with values determined in other species. The assay is specific...
Seasonally inhibited development of cyathostomine nematodes in Shetland ponies in The Netherlands. Two groups of three yearling Shetland ponies were used in 1988 to study the epidemiological significance of inhibited development of the Cyathostomine nematodes. In Group 1, acquisition of infections was prevented throughout the grazing season whereas in Group 2 strongylid infections were acquired from the beginning of July until the end of September. Worm counts showed that the Cyathostomine nematode populations of Group 1 ponies mainly consisted of adult worms and those of Group 2 ponies of inhibited early third stage larvae (L3). These results indicate that a large proportion of Cyathostomi...
Effects of Fusarium moniliforme and corn associated with equine leukoencephalomalacia on rat neurotransmitters and metabolites. Fusarium moniliforme (FM) is associated with equine leukoencephalomalacia (ELEM) and hepatotoxicities in horses and rats. The neurochemical effects of ELEM-associated corn naturally infected with FM and FM strain MRC 826 were studied in rats. Increases in brain 5-hydroxyindoleacetic acid (5-HIAA, major metabolite of serotonin, 5-HT) and 5-HIAA/5-HT ratios were observed in rats fed the ELEM-FM corn. These rats had reduced body weights (17%, P less than 0.01) and increased brain weight/body weight ratios (14%, P less than 0.01) as compared with controls that were fed commercial corn. Rats fed a ...
[Meadow saffron (Colchicum autumnale) in hay and colic in horses]. Following feeding of a new delivery of hay (bought in Southern Germany) 3 horses out of a unit of 17 developed colic within a few days one horse died. Post-mortem there was an intensive accumulation of serous or serous-haemorrhagic fluid in the thorax and abdomen. The hay was heavily contaminated by autumn crocus (colchicum autumnale)--about 1.48% of total mass. Other feedstuffs were of good quality and following removal of the affected hay no further cases of colic occurred. The pathological findings also indicated a colchicine intoxication.
Fibrin/fibrinogen in lungs and respiratory secretions of horses with chronic pulmonary disease. The concentration of soluble fibrinogen derivatives (SFD) and protease and procoagulant activities were determined in cell-free supernatants of equine respiratory secretions obtained from horses with chronic pulmonary disease. The concentration of neutrophils was estimated from direct smears of the secretions. Lung specimens and smears of the secretions were evaluated for the presence of fibrin or fibrinogen by use of immunohistochemical methods. Thirty-five of 80 specimens tested contained SFD. Respiratory secretions from horses with moderate or severe chronic pulmonary disease contained SFD ...
Ataxia in Swedish warmblood and standardbred horses. A radiologic and pathology study. Lesions in the cervical spine of 28 young horses (Standardbred Trotters and Swedish Warmbloods), killed because of longstanding or severe ataxia, are described. The material consists of all horses with ataxia available for necropsy and presented to the large animal clinic of the School of Veterinary Medicine, Uppsala and the Animal Hospital in Helsingborg during 1981 through 1983. After a clinical and radiographic examination, including myelography in all but 2 cases, the horses were killed and necropsy was performed. The cases were divided into three categories based on the radiographic and p...
Secondary gastric impaction associated with ragwort poisoning in three ponies. Poisoning with Senecio jacobaea (ragwort) is a common cause of chronic liver disease in horses in Britain. The major clinical signs are the result of hepatic failure but gastric impaction has recently been associated with the disease. The present paper describes three cases of secondary gastric impaction associated with ragwort poisoning. In each case the impaction was the cause of death or necessitated euthanasia.
Epidemiologic study of salmonellae shedding in the feces of horses and potential risk factors for development of the infection in hospitalized horses. A study was designed to identify epidemiologic factors associated with the development and spread of salmonellae in horses in a veterinary teaching hospital, through a case-control study and a longitudinal follow-up prospective study. In the case-control study, 44 horses shedding salmonellae in feces were compared with 99 control horses not shedding salmonellae in feces; regarding breed, sex, age and initial diagnosis, none of the odds ratios for study factors was significant. The factors found to be associated with fecal shedding of salmonellae in the prospective study included diarrhea at th...
Diarrhoea in adult horses: a survey of clinical cases and an assessment of some prognostic indices. Samples of faeces and blood were obtained from 66 adult horses with diarrhoea. The results of routine bacteriological, parasitological, haematological and biochemical tests were correlated with the outcome of the cases. Twenty-two (33 per cent) of the horses died or were destroyed as a consequence of the diarrhoea. A diagnosis was reached in only 23 cases (35 per cent), and in nine of them only at post mortem examination. Salmonella typhimurium was isolated from five cases. Statistical analysis revealed significant differences between the horses which survived and those which died in their pac...
Jugular thrombophlebitis resulting from an anaesthetic induction technique in the horse. Forty-eight hours after general anaesthesia was induced by glycerol guaiacolate and thiopentone sodium in 10 horses, the jugular veins were dissected out at post-mortem and examined visually and histologically. All veins showed a marked thrombophlebitis involving the media and intima at the site of injection. The influence of catheter composition, catheter placement and chemical composition on the occurrence of the thrombophlebitis is discussed. It is concluded that the thrombophlebitis was chemically induced.
Observations on heaves. An asthma-like syndrome in the horse. 1964. Observations in six horses with heaves established a clear relationship between attacks of heaves and the feeding of hay. Severe acute attacks were accompanied by striking changes in the eosinophil count and the sedimentation rate. The variation in the severity of heaves in relation to the feeding and withholding of hay is accounted for by assuming that attacks result from a transient, obstructive lesion in the bronchial tree or lung caused by hypersensitivity to some component of hay. The observations strongly suggest that heaves is a respiratory allergic disease in the horse. The relation of...
Histopathological development of equine cutaneous papillomas. The histopathological development of equine cutaneous papillomas was studied in 78 warts naturally occurring in 50 one to 3-year-old Thoroughbred or Arab horses and in 54 warts experimentally induced in three 2-year-old Thoroughbreds. Lesions in the natural cases were categorized into three phases, growth, development and regression. Main lesions of the growing phase were marked hyperplasia of the basal cells and mild to moderate acanthosis, hyper- and parakeratosis with a few intranuclear inclusion bodies (IIB) which were positive with anti-bovine papillomavirus serum. In the developing phase...
Radiology in racetrack practice. This article focuses on the principles involved in making radiographs of equine limbs; understanding radiographic anatomy, including normal variations; and principles of radiographic interpretation. The influence of pathogenesis of disease on the radiographic image is considered. Diseases associated with racing as well as the developing racehorse are discussed.
Equine laminitis: a potential model of Raynaud’s phenomenon. Raynaud's phenomenon (RP) and equine laminitis in the horse are medical enigmas. Clinical and scientific data were compared to evaluate the degree of similarity that exists between these two peripheral vascular diseases. Data indicate that certain pathologic and pharmacologic aspects seem to have common features. Some of the correlations maybe due simply to both diseases having ischemia of the distal digits as a pathologic component. The exact etiology of the ischemia is not known for either disease. The results of this study suggest the hypothesis that RP and laminitis are the same disease in...
Variation in glycogen and mucins in the equine uterus related to physiologic and pathologic conditions. Histochemical stains were applied to six equine uterine biopsies representative of the physiologic breeding season, Spring and Fall transition, and Winter anestrus periods. These were compared with uterine biopsies from six mares with intrauterine urine pooling, eight mares used to study the uterine response to indwelling catheterization, and necropsy specimens from four pregnant mares at approximately 60 or 100 d of gestation. Alcian blue staining at pH 2.5 or 1.0 was used to identify the presence of carboxylated and sulfated acid mucins or only suflated acid mucins, respectively. Periodic ac...
Pseudohyperparathyroidism in a mare associated with squamous cell carcinoma of the vulva. An 18-year-old Appaloosa mare was examined because of squamous cell carcinoma of the vulva, anorexia with pronounced weight loss, and hypercalcemia. The tumor had developed rapidly over a period of 3 months and externally extended ventrally involving the perineum and the dorsal aspect of the udder. Necropsy examination demonstrated a large primary squamous cell carcinoma of the vulva, perineum, and mammary gland with metastases to the supramammary, sublumbar, deep inguinal, and mediastinal lymph nodes. No gross renal lesions were observed and, histologically, there was only mild vacuolation of...
Ehrlichiosis–a disease of animals and humans. Ehrlichiae are one of several kinds of obligate intracellular bacteria. Taxonomically, they are grouped with rickettsiae, but they can be distinguished by their unique tropism for circulating leukocytes. Ehrlichia canis causes a pancytopenia in dogs that becomes chronic if untreated. Certain breeds develop severe infections, characterized by fever, anorexia, dramatic weight loss, marked pancytopenia, anemia, peripheral edema, and hemorrhage. Ehrlichia risticii, a recently discovered species, is the cause of a serious diarrheal disease of horses. Other species of ehrlichiae have been documented...
Trajectory analysis of winds and eastern equine encephalitis in USA, 1980-5. Backward trajectories of winds were determined to identify possible sources of eastern equine encephalitis virus associated with isolation of virus from mosquitoes or birds or outbreaks in horses between 1980 and 1985 in Maryland, New Jersey, New York and Michigan, USA. The results of the trajectory analyses suggested that eastern equine encephalitis virus could have been carried by infected mosquitoes on surface winds at temperatures 13 degrees C or higher from North Carolina north-eastwards along the Atlantic Coast to Maryland and New Jersey and thence to upstate New York and from western Ke...
[Veterinary examinations of horses during purchase transactions]. Veterinary examinations of horses on the occasion of sale or purchase take place on the basis of contracts for work and services. Three types may be distinguished: Examinations for sale (by order of the seller before the sales contract is concluded) Guarantee examination (by order of the buyer after conclusion of the sales contract) (Real) purchase examination (under a conditional contract of purchase). In the latter case the veterinarian acts as trustee for both seller and buyer and is equally obliged to both parties morally and at law. The deficiencies of the law of warranties for contracts ...
Further observations on Strongyloides westeri dermatitis: recovery of larvae from soil and bedding, and survival in treated sites. Two horses repeatedly underwent episodes of frenzy characterised by extreme discomfort and hyperactivity. Within 2 days of an attack the lower extremities of both hind legs of one subject were uniformly swollen, while on the second subject skin lesions erupted 3-4 days after an attack and swelling persisted for 2-3 weeks. Filariform larvae of Strongyloides westeri were cultured from soil and sawdust where the subjects were kept. Larvae were cultured from soil of low pH (4.5-5.8) but were absent from neutral or alkaline soils. Larvae were found in sawdust with a wide pH range. It is thought tha...
Trajectory analysis of winds and vesicular stomatitis in North America, 1982-5. Outbreaks of vesicular stomatitis, serotype New Jersey, during epidemics in the United States and northern Mexico, 1982-5, were examined by backward trajectories of winds to investigate spread and possible sources. The outbreaks selected for analysis did not involve introduction of disease by infected animals. The findings indicate that wind could have been responsible for carrying infection from northern Mexico to Arizona and New Mexico and thence to Colorado and Utah and on to Wyoming, Idaho and Montana. The results of these analyses are consistent with the findings from T1 RNAse fingerprint...
